FIXMEs for current snapshot deallocation

allocator.go

@@ -76,6 +76,11 @@ type Deallocator struct {
 
 // Deallocate adds node to the deallocation list.
 func (d Deallocator) Deallocate(nodeAddress NodeAddress, srcSnapshotID SnapshotID) {
+	if srcSnapshotID == d.snapshotID {
+		// FIXME (wojciech): Deallocate immediately
+		return
+	}
+
 	listNodeAddress, _ := d.deallocationLists.Get(srcSnapshotID)
 	list := NewList(ListConfig{
 		SnapshotID:    d.snapshotID,

snapshot.go

@@ -23,6 +23,8 @@ type SnapshotConfig struct {
 
 // NewSnapshot creates new snapshot.
 func NewSnapshot(config SnapshotConfig) (Snapshot, error) {
+	// FIXME (wojciech): If it's the already-committed snapshot, mark it as read-only.
+
 	if config.SnapshotID == 0 {
 		config.Allocator.Allocate()
 	}

space.go

@@ -97,6 +97,8 @@ func (s *Space[K, V]) set(pInfo ParentInfo, item DataItem[K, V]) {
 
 			return
 		case stateData:
+			// FIXME (wojciech): Don't copy the node if split is required.
+
 			dataNodeData, dataNode := s.config.DataNodeAllocator.Get(*pInfo.Item)
 			if dataNode.Header.SnapshotID < s.config.SnapshotID {
 				newNodeAddress, newNode := s.config.DataNodeAllocator.Copy(dataNodeData)
@@ -160,7 +162,8 @@ func (s *Space[K, V]) set(pInfo ParentInfo, item DataItem[K, V]) {
 }
 
 func (s *Space[K, V]) redistributeNode(pInfo ParentInfo) {
-	_, dataNode := s.config.DataNodeAllocator.Get(*pInfo.Item)
+	dataNodeAddress := *pInfo.Item
+	_, dataNode := s.config.DataNodeAllocator.Get(dataNodeAddress)
 
 	pointerNodeAddress, pointerNode := s.config.PointerNodeAllocator.Allocate()
 	*pointerNode.Header = SpaceNodeHeader{
@@ -178,6 +181,8 @@ func (s *Space[K, V]) redistributeNode(pInfo ParentInfo) {
 
 		s.set(pInfo, dataNode.Items[i])
 	}
+
+	s.config.Deallocator.Deallocate(dataNodeAddress, dataNode.Header.SnapshotID)
 }
 
 func hashKey[K comparable](key K, hashMod uint64) Hash {